A car battery is used for supplying power to various electrical devices of a car. Moreover, the car battery can also be used for starting a car engine. Generally speaking, the car engine, after being started, can charge the car battery to ensure sufficient power of the car battery. However, for some reasons such as aging, damage or over-discharging, the car battery may not have enough power for starting the car. Some emergency power source products have been developed for starting car in emergency when the car battery fails.
However, the car battery generally has two specifications, i.e. 12 V and 24 V, which can start the gasoline engine and the diesel engine, respectively. The conventional car emergency power source products can only output one of the two specifications 12 V and 24 V, and thus can only be used for starting one of the gasoline engine and the diesel engine. Such products can not satisfy demands of emergency starting of both the two types of engines.
Therefore, there is a continued need for improving the mobile power pack.